Holly cow, on desktop I just noticed the "add category" button (didn't notice it on mobile). As I understand, this is something like "favorite tags". This is actually something that I proposed to be implemented on steemit 2 years ago.
Thank you very much for adding it :D
Ps. I also proposed easy tipping users, which of course wasn't implemented so I made my own version of it :) tip! 2
Yeah, you could not see it on mobile because it is only available on desktop right now :-) But this could change since people are using Steeve on mobile quite a lot it seems.